A total of 100 stool specimens from HIV positive and HIV negative adults and children with acute gastroenteritis submitted to the Microbiology Laboratory (National Institutes of Health) and Virology Laboratory (Georgetown University Hospital) will be used in this evaluation. Four commercial enzyme immunoassay kits will be evaluated. The four kits are: 1) Abbott Testpack (Abbott Laboratories, North Chicago, IL), 2) Difco Rota-Cube; 3) Cambridge BioScience Rotaclone test kit; 4) Pathfinder Rotavirus (Kallestad Laboratories). This study was undertaken to compare the sensitivity, specificity, and predictive values of four commercial assays using a group of specimens representative of stools likely to be submitted to a diagnostic facility for rotavirus testing.